During the first year of this grant proposal we localized the adenylate cyclase in mouse testis at the time of germ cell differentiation. We also made a thorough investigation of testicular biopsy materials from normal and infertile men. We are now investigating the effects of various hormones on adenylate cyclases in human testis. This investigation will provide us with insight into the action of hormone on germ cell adenylate cyclase in mouse and should prove of great value in the study of male infertility.